Brief overview

The modern day industrial societies are concerned with environmental protection and sustainable use of natural resources. A lot of waste is generated by businesses, households and the construction industry globally on daily basis. Engineering has a role in designing ways of effectively managing waste through various means like green technology and exploiting waste to produce alternative sources of energy (Worrell & Vesilind, 2012, p. 71). The management of waste through proper disposal or recycling is important in protecting the environment. Engineering has a great role in ensuring sustainable use of natural resources and environmental protection. Mechanical engineers are actively engaged with how the society uses natural resources. It discovers, designs, maintains, improves and repairs machineries like cars, airplanes and industrial equipment which human beings depend on for their daily lives (Wang & Koh 2010, p. 49). In the future, mechanical engineering will deliver solutions that will sustain and protect the existence of man on the planet. There are two major ways in which engineering can help in mitigating the problem of waste management which are preventing waste in engineering and management of waste. The next section will look at the two methods, their advantages, disadvantages and cases where they have been used successfully.
Waste prevention (Designing out waste in mechanical engineering)
Green manufacturing is an emerging concept in engineering that aims to achieve sustainable development in the manufacturing industry. Dornfeld (2010, p. 56) defines green manufacturing as the creation of manufactured products that use processes that conserve energy and natural resources, are non-polluting and are economically safe and sound for users. There is an increasing need for mechanical engineers and engineering in general to innovate new ways of creating products that minimise waste of resources. Rynn (2010, p. 87) asserts that for mechanical engineering to be able to design products that are friendly to the environment, issues of sustainability should be part of all the decision making processes in engineering. This covers all the steps from product design to its end life and after that the needed efforts in regaining its value rather than disposal.
The main objective for green manufacturing is to produce products that can be remanufactured, recycled or reused. As such green manufacturing process reduces the environmental impact of a manufacturing process than it was in the past. Green manufacturing systems include measures to reduce the volume of hazardous waste produced, change the energy mix to include the use of more renewable resources and cut down the volume of coolant consumed in the manufacturing process. The other measure that reduces waste of resources is lean manufacturing which has been successfully used by Toyota in its manufacturing plants. The lean manufacturing system as used by Toyota managed to reduce seven types of wastes in the company’s manufacturing process. Toyota reduced overproduction, inventory, transportation, motion, over processing, defects and waiting times (International Conference on Mechanical Engineering and Green Manufacturing & Li 2010, p. 77). Most of these wastes are related to the desire to minimise the environmental impacts of the manufacturing process. For instance, a reduction in the waiting times saved company resources like lighting and air conditioning. Many machines used in the production process consume a lot of energy even when not processing any products. As such the idle time used for allowing the smooth flow of products wastes a lot of energy.
The lean manufacturing processes, initiatives, strategies and techniques are advantageous in terms of reducing operational costs and also aim at boosting, restoring and significantly improving organisational competitiveness. Lean manufacturing reduces the manufacturing time by eliminating the wastes in the manufacturing process. A reduction in manufacturing time leads to a subsequent reduction in operational costs in the form of labour, energy and other utilities. In so doing, it helps organisations in retaining, maintaining and significantly increasing their revenues, widening their margins and generation of savings from lowering costs. Lean manufacturing helps companies in saving space which raises the levels of efficiency and savings. According to Davim (2013, p.64), lean manufacturing has a potential of increasing the productivity of a company by approximately 75% to 125%. This is because the elimination of wastes and any other unnecessary practices at the workplace assists the employees to work without distractions and in so doing maximise output. The elimination and reduction of waste in the production process helps the companies in increasing earnings and profits by reducing wasteful use of resources. In addition to this, the elimination of unnecessary tasks and job positions helps companies in reducing labour expenses and in return increase their earnings (Skrabec 2013, p. 33).
Despite the aforementioned benefits that come with lean manufacturing, there are various barriers that prevent organisations from fully implementing it in their manufacturing processes. The capital cost requirements of emission control and waste management are extremely high with long payback period (Worrell & Vesilind, 2012, p. 88). This makes it very difficult for most companies as this translates into higher product prices which would drive away potential customers. In other instances the capital input exceeds the direct economic gains thus frustrating the successful implementation of green manufacturing. The other barrier is that the manufacturing industry relies on certain technologies and processes that may cause undesirable effects but cannot be ignored like the volatile organic compound used in automotive manufacturing.

Waste management (use of recycling and reuse)

Waste management entails reducing the amount of waste that the manufacturing industry disposes on the environment (Kühnle 2010, p. 96). In reusing and recycling of waste products, the manufacturing industry reuses old or waste products to produce new products. Waste management reduces environmental pollution, energy usage, air pollution, water pollution and consumption of fresh raw materials by reducing the reliance on conventional waste disposal (Hesselbach & Herrmann 2011, p. 54). The manufacturing firms should therefore aim at reducing waste at each and every phase of the production process. The first step is to identify the areas where waste is high in the manufacturing process and then find out what needs to be recycled using cost benefit analysis. Nikon has successfully managed to do this and is recycling its wastes to produce new products.
Recycling of old products is important because it helps in environmental conservation. Reusing of resources relaxes the strain placed on natural resources which are increasingly getting depleted. The other advantage of recycling old products is that it reduces energy consumption (Shina 2008, p. 65). The manufacturing process uses large amounts of energy in processing the raw materials into finished products. Recycling helps the manufacturing companies in minimising energy consumption which is important for massive production like refining and mining. In addition to this, it also makes the production process effective in terms of cost which raises the margins for the manufacturers (Association for Manufacturing Excellence 2008, p. 162). Although product recycling is very beneficial to the manufacturers, there are some barriers that hamper the successful implementation of recycling old products in the manufacturing process. The first barrier is that the recycling process is not always cost effective because at times companies are forced to open up new factories thus raising their operational costs (Wang et al 2011, p. 22). A new factory by itself may even cause more pollution in terms of transportation, cleaning and storage. Other than operational challenges, the other major limitation of recycling is that the recycled products are not always as durable as the original products. Products made from trashed waste are cheap and less durable and may not generate sustainable revenue for organisations like other products.

Key lessons learnt and how these can be used to improve the future

Both lean manufacturing and waste reuse are important in reducing wastes that emanate from the manufacturing processes. Lean manufacturing should be used in eliminating wastages in the production process in order to ensure that organisations minimise operational costs. However, the findings reveal that both methods should be implemented in the manufacturing process in order to improve the waste management in mechanical engineering.

Key conclusions and recommendations

Waste management should be included in all the stages of the manufacturing process in order to ensure sustainability in engineering. Owing to the fact that the quality of recycled products is often lower than the other original products, it is recommendable to embrace lean manufacturing in order to ensure that wastages are eliminated in the production process.